1. Field of the Invention
The present invention relates to a storage system and a backup method therefor, and it can be preferably applied to, for example, a 3 data center (3DC) system.
2. Description of the Related Art
There is a technique conventionally known as a disaster solution (disaster recovery) for a storage system, by which backup data for data in a storage apparatus operated at a certain site is managed at a different storage apparatus located away from that site (this technique is hereinafter called the “remote copy”), and various related techniques have been suggested (Japanese Patent Laid-Open Publication No. 2005-25683).
For example, Japanese Patent Laid-Open Publication No. 2005-25683 discloses a technique where backup data for data stored in a first storage apparatus is stored in a second storage apparatus, and the backup data is immediately read from the second storage apparatus and compared with the data in the first storage apparatus in order to guarantee data and enhance reliability.
Moreover, recently, many techniques have been suggested regarding a storage system called 3DC, where data stored in an operating first storage apparatus is managed at two other storage apparatuses, a second storage apparatus and a third storage apparatus, located away from each other as well as the first storage apparatus (Japanese Patent Laid-Open Publication No. 2004-206562).
For example, Japanese Patent Laid-Open Publication No. 2004-206562 discloses a technique where, among three storage apparatuses respectively located at three sites, backup data for data stored in a first storage apparatus, which is set as a copy source, is also managed at second and third storage apparatuses which are set as copy destinations, and if a failover execution request is transmitted from a host computer, a copy of the data stored in the first storage apparatus is managed by one of the second storage apparatus or the third storage apparatus, which is set as a spare.